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In PQ News
Call of the Month for May 2026 Via EPRI’s Power Quality Knowledge (PQK) Hotline, a PQK funder raised questions about elevated third-harmonic voltage and Voltage Total Harmonic Distortion (VTHD) measured in medium-voltage (MV) distribution systems. Of particular concern to the member utility, these levels appeared to exceed the limits prescribed in IEEE 519 for extended durations, including periods lasting several hours or even days. Sustained harmonic distortion of this nature is often associated with resonance conditions within the power system.
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EPRI Industrial PQ Training Videos
As a follow-up to our Industrial Power Quality training classes, we have posted these complementary training videos to help solidify the concepts for both utility members and their customers. The top three are listed here.
Visualizing PQ Drive Parameters for Improved Voltage Sag Ride-Through 
This video demonstrates the voltage sag susceptibility of AC drive systems and how to improve the drive’s robustness through parameter changes.
Understanding PLC Voltage Sag Ride-through: AC and DC Powered Systems
This video demonstrates the differences in voltage sag ride-through between an AC powered PLC system and a DC Powered PLC system.
Power Conditioning to Enhance Control System Voltage Sag Ride-Through: The Constant-Voltage Transformer
This video shows how a CVT can be utilized to harden the voltage sag response of an automated control system.